Importance

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Abstract

A vacuum valve includes a valve body with a cylindrical sidewall having a vacuum inlet coupled to a vacuum source and a vacuum outlet. A piston is disposed within the valve body for movement between an open position and a closed position and provides a vacuum port that extends between the vacuum inlet and the vacuum outlet when the piston is in the open position. The valve also includes means for cooperating with a vacuum source to remove material from the vacuum valve as the piston moves between the open and closed positions. The vacuum port of the piston includes a reduced diameter portion that provides a passageway for vacuum and debris. A sharp edge, preferably an annular knife edge, circumferentially surrounds the piston adjacent, and extending into, the reduced diameter portion. The annular knife edge is oriented to provide a cutting stroke during movement of the piston from the open position to the closed position. As the piston moves from the open position to the closed position, the annular knife cuts any debris remaining in the vacuum inlet or outlet and retains the debris in the reduced diameter portion until the piston moves back to the open position, whereupon the vacuum from the vacuum source sucks the debris out of the valve.

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First Claim